The present invention relates to a vehicle travel time estimation method. The invention also relates to a computer program product.
Running a profitable work site, such as a gravel pit or construction site, requires a lot of logistic planning with many interrelated activities. For example, the loading process of a wheel loader or excavator, the travel time for transportation vehicles etc. must be estimated. Some activities, such as the loading process of a wheel loader or excavator are rather easy to estimate due to that the process consists of a number of well-defined operations. However, it is far more complicated to estimate the travel time of a transportation vehicle.
In order to equip the work site with appropriate vehicles professionals today simulate the transportation vehicles route, taking into account several vehicle parameters such as motor power, capacity, gear transmission, wheels, etc, and also taking into account the route's characteristics including e.g. length, road type, inclinations etc.
When comparing travel time for say five alternative vehicles, each with five alternative configurations traveling on five alternative routes, there are 125 simulates to be conducted and compared. Moreover, each simulation requires heavy computing capacity and quite some computational time. The comparisons are often performed together with the client in an on-site demonstration, where both computing capacity and time are strictly limited.
Therefore, there is a need for a travel time estimation method, where vehicle parameters and road conditions are considered, that does not require heavy computing capacity and significant time.
It is desirable to achieve a travel time estimation method and computer program product where vehicle parameters and road conditions are considered, that does not require heavy computing capacity and significant time.
The inventor has realized that by providing a method that divides a route into sections with substantially constant road characteristics and utilize a database with traveling data for vehicles on the route sections, a total travel time may be estimated with limited computing capacity in a few seconds or less. Moreover, the inventor has realized that if considering the incoming speed from a preceding section when estimating the travel time for each section, the total travel time estimation may be estimated with increased accuracy.
According to a first aspect of the inventive concept, a method is provided for estimating a travel time for a vehicle comprising the steps of: determining a route for which the travel time is to be estimated; dividing said route into route sections, wherein each route section has substantially constant road characteristics; selecting a vehicle configuration for said vehicle; retrieving, from a database, an estimated travel time for each route section based on each route section for said selected vehicle configuration; and aggregating the estimated travel times for each route section from the database into a total travel time for said determined route.
In the context of the application “substantially constant road characteristics”, should be understood as a route section allowing for substantially the same vehicle performance. Thereby, a substantially constant road characteristic means that the characteristics may deviate within a predetermined range. Limitations may be set so that e.g. for a route section to be defined as a “leveled straight road section” the predetermined range may be that the inclination may not exceed ±2%, and the section may not comprise curves with smaller turning radius than 50 meter. Moreover, as another example, a steep uphill route section may be any uphill exceeding 15% inclination, a medium steep uphill route between 10%-15% etc. Depending on how accurate estimations desired, the limit values for when e.g. a straight leveled route section becomes a curve or an uphill/downhill may be altered.
By providing a method for estimating a travel time for a vehicle as described above, it is possible to perform on-site demonstrations where time is precious and computing capacity very limited. Thereby, a method requiring less time and less computing capacity when trying to find the best fleet of vehicles is provided. Further, the fact that less computing capacity is required means that the agility is increased for anyone that wants to estimate the travel time. Moreover, by saving time and allowing for agile and ubiquitous estimation of travel time, ultimately a better service may be provided for a potential owner of a vehicle fleet.
Moreover, since the computing capacity required to perform the method described is so limited, the method allows for comparing a plurality of different routes and vehicle configurations substantially simultaneously. Thus, hundreds of combinations of routes and configurations may be conducted without the operation requiring hours of data computing. Instead, the comparisons may be conducted in seconds, or even fractions of seconds.
In one embodiment, the database comprises traveling data corresponding to said vehicle accelerating up to a predetermined cruising speed. When the database comprises traveling data corresponding to said vehicle accelerating up to a predetermined cruising speed, the database may allow for estimating the vehicle's travel time for an accelerating portion of the route section. Thereby, a more accurate estimation may be provided for a vehicle traveling a route section.
In the context of the application a “cruising speed”, should be understood as substantially the speed a vehicle would travel on a route section if the section was infinitely long, i.e. a speed corresponding to a state of speed equilibrium. Thereby, the cruising speed in an uphill route section would be lower than a cruising speed in a downhill section, if all other parameters are kept constant. Thus, the cruising speed is affected by the physical circumstances. Substantially constant road characteristics may therefore be essentially similar road characteristics.
In yet one embodiment, the database comprises traveling data corresponding to said vehicle traveling in a predetermined cruising speed. When the database comprises traveling data corresponding to said vehicle traveling in a predetermined cruising speed, the database may allow for estimating the vehicle's travel time for a cruising speed portion of the route section. Thereby, a more accurate estimation may be provided for a vehicle traveling a route section.
In one embodiment, the database comprises traveling data corresponding to said vehicle decelerating to a predetermined cruising speed. When the database comprises traveling data corresponding to said vehicle decelerating to a predetermined cruising speed, the database may allow for estimating the vehicle's travel time for a decelerating portion of the route section. Thereby, a more accurate estimation may be provided for a vehicle traveling a route section.
In yet one embodiment, the database comprises traveling data corresponding to braking said vehicle from a predetermined max speed to substantially standing still. When the database comprises traveling data corresponding to braking said vehicle from a predetermined max speed to substantially standing still, the database may allow for estimating the vehicle's travel time for a braking portion of the route section. Thereby, a more accurate estimation may be provided for a vehicle traveling a route section.
In one embodiment, the traveling data comprises distance, speed and time data. The traveling data may comprise what speed the vehicle would have at each time unit until a cruising speed is reached, or what speed the vehicle would have at each traveled distance until a cruising speed is reached. Thereby, the calculations of estimated travel time may be conducted with the simple rules of arithmetic.
In yet one embodiment, the traveling data comprises acceleration and any one of speed, distance or time data. The traveling data may comprise what acceleration the vehicle would have at each time unit or traveled distance, until a cruising speed is reached when the acceleration would be substantially zero. Thereby, the calculations of estimated travel time may be conducted with the simple rules of arithmetic.
In one embodiment, the traveling data further comprises fuel consumption. Thereby, not only the travel time may be estimated in the method, but also the fuel consumption of the travel may be estimated. This may be of great interest for a potential fleet vehicle owner, whom most likely would pay the fuel for the vehicles. By considering the cost of fuel for each evaluated vehicle and adding the aspect of estimated travel time, an even better basis for deciding on what vehicle to choose may be obtained. In fact, the fuel costs typically amount to about 50% of the total costs for running a gravel pit. Moreover, it would be possible to estimate when the vehicle need to refuel, and thus be idle for a moment.
In further embodiments, the traveling data may comprise energy consumption. Thereby, if the vehicle is an electric vehicle it is also possible to estimate when and how often the vehicle needs to charge the batteries. This is a great advantage, as charging a battery often require quite some time, making the vehicle idle during that time. Moreover, the cost for the used energy may be calculated.
In yet one embodiment, the estimated travel time for each route section is dependent on the traveling data of a previous route section, unless the route section is the first route section of the route. Thereby, the route section may be handled dynamically, and depended on each other, resulting in that the accuracy of the travel time estimation may be increased substantially.
In one embodiment, the estimated travel time for a route section is estimated by the partial steps: determining the vehicle's final speed at the end of the directly preceding route section, and assigning said final speed from the preceding route as an initial speed for the current route section. Since the vehicle's speed in any section is linearly related to the travel time, the speed of the vehicle in each section affects the estimated travel time. By considering the final speed in a first route section and relating it to the initial speed in a second route section, the accuracy of the estimated travel time may be increased. E.g. if comparing the travel time for a 40 meter long straight leveled route section, the travel time would be shorter if the vehicle is coming from a fairly long downhill route section with a relatively high speed, than if the vehicle would come from an uphill route section, with a substantially lower speed. Simply put, the average speed in the route section is affected by the incoming speed in the route section which is determined by the final speed obtained in the previous route section.
In yet one embodiment, the route sections are divided into vehicle speed curves, wherein each vehicle speed curve represent one of: said vehicle accelerating up to a predetermined cruising speed, said vehicle traveling in a predetermined cruising speed, said vehicle decelerating to a predetermined cruising speed, or braking said vehicle to substantially standing still.
In yet one embodiment, the estimated travel time for each route section is estimated by estimating each travel time for at least a portion of any relevant speed curve and subsequently aggregating the travel time for said portions of any relevant speed curves into a travel time for each route section. Thereby, each route section may be divided into speed curves, and relevant portions of each speed curve may be used to estimate the travel time of the route sections. For example, to estimate the travel time of a first section, a travel time for a speed curve starting with the vehicle standing still and running until the cruising speed may be estimated. Thereafter, the estimated travel time for the remaining portion of the section may be estimated by estimating the travel time of the vehicle traveling in a cruising speed in the remaining distance of the route section. This is further explained in the detailed description below. Thereby, the method's accuracy is increased with simple means.
In yet one embodiment, the selected vehicle configuration comprises at least one of motor power, weight, load, fuel consumption and gear transmission. Thereby, parameters affecting the vehicles performance which in turn affects the travel time may be considered. Thus, the accuracy of the travel time estimation may be increased.
In one embodiment, the road characteristics comprise at least one of distance, inclination, rolling resistance, and bend of a curve. Thereby, parameters of the route affecting the vehicles performance which in turn affects the travel time may be considered. Thus, the accuracy of the travel time estimation may be increased.
In yet one embodiment, the method further comprises the step of determining the driver characteristics of the driver of said vehicle, and wherein the database further comprises traveling data corresponding to driver characteristics. Since different driver characteristics would generate different traveling times, a more accurate travel time may be estimated by also considering the drivers characteristics. E.g. a driver looking to minimize fuel consumption, e.g. by applying of the concept of ECO-driving, would generate a different speed profile than a driver looking to merely minimizing travel time.
According to a second aspect of the inventive concept, above and other aspects of the inventive concept is achieved through a method for creating a database for use of estimating a travel time for vehicles, comprising: defining a plurality of vehicles, each vehicle with a plurality of configurations, for which the travel time is to be estimated, defining a plurality of route sections, wherein each route section has substantially constant road characteristics, generating a database comprising traveling data corresponding said defined vehicles traveling along said route sections.
Wherein the traveling data comprise vehicle speed curves representing: said vehicles accelerating to a predetermined cruising speed, said vehicle traveling in a predetermined cruising speed, said vehicle decelerating to a predetermined cruising speed, or braking said vehicle to substantially standing still.
Thereby, a database to be used for estimating a travel time for vehicles could be generated. By generating the database in advance, less time and computer capacity is required when travel time estimation of a vehicle is needed. Moreover, the advantages of the invention according this aspect are substantially analogous to the advantages as stated above.
According to a third aspect of the inventive concept, above and other aspects of the inventive concept is achieved through use of the database formed according to above for estimating a travel time for a vehicle according to any of the embodiments as described above. The advantages of the invention according this aspect are substantially analogous to the advantages as stated above.
According to a forth aspect of the inventive concept, above and other aspects of the inventive concept is achieved through a computer program product comprising a computer readable medium having stored thereon computer program means for estimating a travel time for a vehicle, wherein the computer program product comprises: code for determining a route for which the travel time is to be estimated, code for dividing said route into route sections, wherein each route section has substantially constant road characteristics, code for selecting a vehicle configuration for said vehicle, code for retrieving, from a database, an estimated travel time for each route section based on each route section for said selected vehicle configuration, and code for aggregating the estimated travel times for each route section from the database into a total travel time for said determined route. Thereby, a computer program product may enable the use of a database for estimating a travel time for vehicles. Thereby, less time and computer capacity is required when travel time estimation of a vehicle is needed. Moreover, the advantages of the invention according this aspect are substantially analogous to the advantages as stated above.
The computer readable medium may be one of a removable nonvolatile random access memory, a hard disk drive, a floppy disk, a CD-ROM, a DVD-ROM, a USB memory, an SD memory card, or a similar computer readable medium known in the art. The present invention may be implemented using a combination of software and hardware elements.
Further features of, and advantages with, the present invention will become apparent when studying the appended claims and the following description. The skilled addressee realize that different features of the present invention may be combined to create embodiments other than those described in the following, without departing from the scope of the present invention.